KR20050000379A - Method for determining the rotational speed of a part, ascertaining the slipping of a continuously variable transmission (cvt), and for controlling a cvt, and a conical disc flexible drive transmission - Google Patents

Abstract

The method involves determining the revolution rate of the part from a number of components in a system subject to oscillations that are coupled in relation to their rotatability by measuring the revolution rate of a component in or at an oscillation node and computing the revolution rate of the part from the measured revolution rate and the transmission ratio between the component and the part. An independent claim is also included for the following: a method of determining the slipping of a continuously variable transmission or CVT, a conical disk gearbox and a method of controling a CVT gearbox.

Description

METHOD FOR DETERMINING THE ROTATIONAL SPEED OF A PART, ASCERTAINING THE SLIPPING OF A CONTINUOUSLY VARIABLE TRANSMISSION (CVT) , AND FOR CONTROLLING A CVT, AND A CONICAL DISC FLEXIBLE DRIVE TRANSMISSION}

Increasing use in power vehicles of transmissions with continuous transmission ratios, the so-called continuously variable transmission (CVT) (e.g., conical pulley belt transmissions, friction gear transmissions, etc.), for convenience and fuel saving, operating as a control unit It relies on the accelerator pedal and the input operated by one hand of the driver, satisfies the dynamic characteristics of the vehicle, and saves fuel. 1 shows a power system of a vehicle.

The vehicle has an engine 2 and is connected to a clutch 4, a transmission 6, a propulsion shaft 8, a differential gear 10, a drive shaft 12, and a rear wheel 14. The front wheel 16 is not shown in the figure.

The electronic control unit 18 with microprocessor and storage device has an input 20 connected to the sensor. The sensor 22 senses the rotational speed of the gear input shaft and is provided with a throttle balance sensor 24, an engine speed sensor 26, a wheel speed sensor 28 and other sensors. An output of the control unit 18 is connected to an actuator of a power transmission system such as a clutch operating device 32, a gear operating device 34 and, if necessary, a throttle valve adjusting unit.

The figure provided is CVT and the actuator 34 is hydraulic. The selector 36 operates several programs, including reverse.

Many problems arise in the actual operation of the CVT power train. To use CVT for a long time reliably, this must be solved. In order to control the CVT, the rotation speed of the input shaft must be known. Due to vibrations in the power system, it is limited to know the exact number of revolutions of the input shaft. Moreover, it is necessary to detect slippage occurring in the frictional connection of the CVT. In the case of a conical pulley belt transmission, the speed ratio is also an important issue since the pair of conical pulleys has one pressure chamber for pressure and adjustment.

The present invention relates to a method for determining the number of revolutions between a plurality of parts that make up a torque vibration system. The present invention relates to a method for determining the sliding of a CVT and a method for controlling a CVT. The invention further relates to a conical pulley belt system.

1 is a view showing a power system of a vehicle.

2 is a diagram for explaining early detection of slipping;

3 is a hydraulic circuit diagram of a conical pulley belt transmission.

Figure 4 is a prior control characteristic chart for opening the valve.

5 is a side view of the conical pulley belt transmission.

6 is a side view of the side rail;

* Symbol description *

6 .... Transmission 38 .... Input shaft

10 .... Differential Gear 40 .... Conical Pulley

12..Drive shaft 46 .... Output shaft

It is an object of the present invention to provide a countermeasure for the above problem.

The method of measuring the rotational speed of a device with rotational vibration is to measure the rotational speed of the vibration node and calculate the rotational speed from the rotational speed and the speed ratio between the parts.

If on the other two sides of the vibrating node of two parts, it is advantageous to use the average number of parts to calculate the number of parts.

The method is used to determine the input speed of the CVT obtained from the power system of the vehicle. The speed of at least one wheel driven by the CVT is measured and the input speed is calculated from the gear ratio of the CVT.

Measuring at least one wheel revolution as well as the CVT's input force revolution is advantageous for using the gear input revolution and is calculated with the measured parameters and speed ratio.

The measured gear input speed and the calculated speed are used to weight the control and / or adjustment of the power system.

It is advantageous that the weight depends on the transmission ratio of the CVT.

The method of measuring the sliding of the CVT is to measure the change in the transmission ratio. The measured change is compared with a predetermined value, and the slip is determined when the difference between the measured value and the predetermined value is more than the predetermined level.

The maximum value of the calculated rate of change is 1 / gear ratio ⁿ and n is 1.5 to 2, and the slip is defined when the rate of change exceeds the maximum rate of change.

Another method of determining the slip of the CVT is at least one audible parameter of the CVT that changes when the slip accumulates, and the slip is established when the measured value approaches the accumulated value in this way.

The advantage of the above method of determining the CVT slip is that by measuring a temporary change in the input rotational speed of the transmission, it is possible to know the slip that will occur soon. Another advantage is that the impending slip can be detected by detecting a temporary change in the force acting on the wheel brake. Once a slip or impending slip is set, the CVT's parameters are adjusted.

The method of controlling a CVT consisting of two pairs of conical pulleys and a belt consists of a single pressure chamber with hydraulic pressure to adjust the contact force of the pulleys and a cross-sectional hole of the control valve installed in the belt and hydraulic lines to change the CVT's transmission ratio. The difference is controlled in advance by a predetermined value.

Conical pulley belt transmission with two pulleys (adjustable distance between them), the belt is wound on the conical pulley, the slide rail guide is at one end of the belt and the rib is on the other side parallel to the belt, and the tube is in the center of the rib Are arranged.

The tube contains at least one additional hole, from which the spray liquid is directed directly to the other side.

It is an advantage of the present invention to evaluate the slip occurrence measured and recorded on the control unit of the vehicle. The output of the slip depends on whether it exceeds the specified range. Experiments have shown that not all slips lead to gear damage. Damage at large outputs does not necessarily lead to permanent damage, but one or more limit values are introduced. Corresponding tables can occur either directly in the vehicle or in the workshop.

The output P of slip with respect to time is determined as follows.

P = M x Δω

Where M is the torque of the transmission gear and is measured at the contact pressure sensor, and Δω is measured as the derivative of the angular velocity and the excess gear ratio resulting from the slip between the sliding chain and the gear.

The maximum value of the output P determined in this method is used for comparison. This value can also be used as an integral or statistical approximation to the time of output. The more accurate method of using the maximum value depends on the performance of the processor of the control unit.

This shows a range of slip levels in the power range, for example, minor damage up to 5.10 kW, and more serious damage. The number of slips is recorded in the error memory according to this classification. The error counter is weighted when a slip is added.

The control of the transmission 6 is based on the input rotational speed of the transmission by the control unit 18. The input speed is measured directly, and the measured signal contains harmful frequencies, which adversely affects the speed ratio control. In extreme cases, feedback occurs that affects transmission ratio control. For this reason it is desirable to have a signal that does not include vibration or to a limited range. Strong filters with high time constants are not allowed because they blunt the dynamics.

The solution to this problem is to measure the number of rotations of the low vibration tendency in the region of the vibration technology point forming the vibration node.

A power system connected by shafts consisting of engines, transmissions, and tires facing the road is a system that can generate rotational vibration. Here, the engine and the transmission can vibrate with respect to the weight of the vehicle, the natural frequency is 7.1 Hz and the secondary speed is 212 rpm. In other cases, when the transmission vibrates between the engine and the vehicle, the natural frequency is 19.8 Hz and the secondary speed is 593 rpm. In another case, when the wheel vibrates between the transmission and the vehicle, the natural frequency is 47.9 Hz and the secondary speed is 1,436 rmp. In another case, when the gear input vibrates between the motor and the rest of the output shaft, the natural frequency is 71.4 Hz and the secondary speed is 2,143 rpm. In the case of a conical pulley belt transmission, the speed ratio of the gear (conical pulley pair and belt) can be calculated by measuring the rotational speed of the first conical pulley pair and the rotational speed of the second conical pulley pair. Since the transmission gear of the vibration technology point is very rigid, no harmful frequency is generated. Wheel speed is obtained from ABS control unit. The number of revolutions of the wheel is measured directly at the wheel, not at the gear unit, and includes harmful frequencies.

At the measured wheel speed and speed ratio, the gear input speed nb is calculated by the following equation.

(1) nb = icvt * ip * nr

icvt is the CVT, ip is the differential gear, and nr is the wheel speed.

If there is an additional gear step between the input disc pair of the CVT and the input shaft of the differential gear, the gear ratio can be added.

The vibration node is located in two measuring zones. The vibration resistance signal is generated as an average of the rotation speeds measured at both sides of the vibration node.

As the above method, the power system vibration of the transmission ratio control is improved. The risk of effects of high amplification is eliminated. The control characteristics can be improved with high allowable control amplification.

The described method is applicable to all kinds of CVTs. Examples are friction gears, conical pulley belt transmissions, and the like. Especially when changing the gear ratio, CVT can be a source of harmful vibrations.

The gear ratio of the conical pulley belt transmission is adjusted by varying the contact pressure between the pulley and the belt. This change is caused by selecting a hydraulic valve that regulates the pressure. By complex adjustment of the belt transmission characteristics (speed, torque, speed ratio, contact force), the control circuit calculates the actual speed ratio from the measured speed, and the target speed ratio is calculated according to the current driving situation (speed, gas pedal operation). ). Furthermore, the actual gear input rotation speed is measured in the control unit to determine the target rotation speed. The control unit not only reacts quickly to the target / actual difference, but also limits the change in revolutions to the current situation.

The measured actual input speed is not directly used as the input value. First, the gear ratio is calculated from the input and output values, and the gear ratio at the gear input is calculated. This has the advantage that no special filter is required. By shielding and buffering harmful vibrations, the convenience and control quality of the CVT are improved.

The input speed ne of the transmission is determined by the following equation.

(2) ne = a x nb + (1-a) x ng

nb is an input rotation speed calculated based on Equation (1), ng is a directly measured input rotation speed, and a is a weight. If a = 0 then only the measured input speed is used, and if a = 1 the calculated input speed nb separated from the noise is used. If a> 1, the control unit generates a reverse interlock situation. If a <0, it is reproduced by the control unit. Depending on the structure of the control unit, by selecting the appropriate a, the control of CVT reduces the harmful vibrations.

The control unit according to the invention can use a fixed a. The value a is advantageously dependent on the current transmission ratio. Hazardous vibrations can occur within limited transmission ratios. The required a can be derived from harmful vibrations. Hazardous vibrations can be detected using filters.

Another problem with CVT is that there is not enough friction between the parts, which can't transmit torque and slip, causing permanent damage to the transmission. Slip is not detected by only assessing the speed difference because the variable speed ratio is not a fixed value.

Slip detection according to the present invention is to use the transmission ratio gradient (gradient). CVT has a fixed speed. Changing the speed ratio requires a certain duration. If the rate of change of the transmission ratio exceeds the non-slip range, slip can be inferred.

According to the belt wrap principle of CVT, the maximum adjustment speed is not constant but depends on variables such as rotation speed, torque and speed ratio. The biggest impact is the current gear ratio. Theoretically, the maximum speed ratio change rate is 1 / speed ratio ⁿ . n = 2 is the maximum allowable value, and 1.5 to 2, usually 1.7, is an appropriate value. The allowable speed ratio change rate is approximately equal to the adjustment direction.

The maximum allowable speed can be determined as the gear ratio. In the above equation, the maximum adjustment speed for shifting can be calculated. At the present time, the speed of rotation is filtered and remeasured at different frequencies to calculate the maximum adjustment speed. Filter and remeasurement algorithms can be used for the transmission ratio.

In order to change the speed ratio quickly, the adjustment rate of change may exceed the limit. In this case, the slip monitoring is stopped in order to prevent an error of the control unit. The occurrence of slip at low rates of change is beyond the limit when slip is reduced.

In a variant of the method, the change in the variable speed ratio is calculated in a mathematical model as other operating parameters such as engine speed, gear input, speed ratio, input torque, temperature, axial force. The kinematic dynamics di / dt are calculated from these variables during operation. i is the speed ratio. If the difference between the actual value and the calculated value is over a defined range, slippage occurs at this point.

Low limits are defined for fixed dynamics. Underneath it, no calculation takes place. In this method, only a small expected adjustment rate of change slip is detected due to the inaccuracy of the figures.

Due to the computation time, the mathematical model can be simplified considering only the main influence parameters. In conical pulley belt transmissions, the adjustment dynamics mainly depend on the axial force and the speed of change of the speed ratio. Axial force cannot be expressed as an absolute value and is the derivative of the force at a stable point in time.

Next is the derivative of power.

Fdiff = Fs1-ξ x Fs2

ξ is the ratio of the force between the first disk pair and the second disk pair in the normal operation state of the gear ratio = Fs1_stat / Fs2_stat and Fs1 or Fs2 is the force applied to the first or second disk pair.

The transmission ratio is expressed by the following equation by adjusting the coefficient k1 (depending on the transmission ratio i and the adjustment direction).

(3) di / dt = ki x (Fs1-ξ x Fs2)

k1 may be stored in a characteristic line for upshift or backshift.

In CVT, the acting force for the adjustment to calculate or measure is derived. From the kinematics of equation (3), we can see whether something else happens, such as the adjustment or the sliding.

Another method of detecting slip is audible analysis. Solid-borne and / or ultrasonic sensors can be installed in the connection of the pulley's axis or solid-bone sound and can detect eigensound or natural scales. If the audible sound characteristic of the transmission is measured and recorded in this way, it is determined that a slip has occurred in the current audible value or its development.

In this method of detecting slippage, the measurement time is very short (increase the contact pressure of the pulley in the CVT by electronic control). Since a certain time is required for signal processing, fast measurement time is required. Immediate sliding information is provided to increase the contact pressure in time.

The advantage of the early slip detection method is to make a temporary change in the output speed nab when the temporary value exceeds a defined limit. In the measurement of various vehicles, it is due to the slippery braking force of the CVT or the temporary difference in the output speed of the transmission due to ABS. Due to the anti-skid wheels, high torque is applied to the power system and slipping occurs in the CVT without countermeasures. The advantage of using dnab / dt is to detect the slip immediately and get the reaction time and calculation time. The measured change in the two or three output revolutions is calculated as an average value in a very short time. This average reduces the change within a given rate of change. Including too many variables in the work for calculating the mean loses the time advantage of the method, which is undesirable.

In order to avoid slipping in this method, a fully electronically controlled contact pressure or a torque sensor for electronic control can be added. (Motors, additional valves, etc.).

Furthermore, it is advantageous to combine the method of determining the temporary change in the output speed and the method of determining the temporary change in the transmission ratio of the CVT. This method can be applied to unbranch and power-branch transmissions like other methods.

In Figure 2, the advantages of the described method are shown. The time is plotted on the x-axis and the measurement results from 94.6 seconds to 96.4 seconds are shown. The di / dt curve is the instantaneous change of the transmission ratio i of the CVT, and the dnab / dt curve is the instantaneous change of the output rotational speed. The "brake active" arrow indicates the start of braking. The "ABS active" arrow indicates the start of ABS operation. The "slippage" double arrow indicates the time during the CVT sliding when there is no correspondence. Line G1 represents a limit above dnab / dt (absolute value). The line G2 represents the limit beyond the instantaneous change of the speed ratio i.

dnab / dt exceeds the allowable limit (G1) before slippage (at the start of the slip), and di / dt does not exceed the allowable limit (G2) until the transmission slips. The time difference between the impending slip and the actual slip is 150 ms and is sufficient to avoid slipping with an appropriate response. The actual value of G1 is for example 1500 to 2000 RPM.

Another way to detect slip early in the CVT is to measure the rate of change of the braking pressure on the wheels. If the instantaneous rate of change exceeds the specified value, the rate of instantaneous rate of change of output speed is determined in a similar way to preventing slippage of the CVT.

3 is a hydraulic circuit diagram of the CVT.

The input shaft 38 drives the first conical pulley pair 40, which is connected to the second conical pulley pair 44 via the belt 42 by a friction connection method, which drives the output shaft 46. There is a belt mechanism 42 for adjusting the distance between the pair of conical pulleys by the pressing means. Each conical pulley is in pressure chambers 48 and 50 and is connected to pump 52 by pressure lines and valves.

In the embodiment of FIG. 3, valve A controls the pressure applied to pair of pulleys 42. The valve B controls the input pulley pair 40. Therefore, the contact pressure is regulated by the valve A. The valve is controlled by the control unit 18 (FIG. 1).

The pressure in the pressure vessels 48 and 50 should always be large enough so that no slip occurs between the belt and the pulley. At the same time, the pressure fluctuations must be adjusted between the disc pairs to the desired speed ratio.

The volume of the pressure chamber also changes due to the movement of the pulley during the change of the speed ratio. As a result, a change in the required pressure occurs, and the hydraulic oil does not move without adjusting the speed ratio, and a large flow rate flows according to the adjustment speed required during adjustment.

The contact pressure according to the rotational force depends on the friction law. The required pressure regulation is supplied to the gear ratio controller. The pressure regulation of each pressure chamber is based on the type of pressure chamber. The difference in control is a good way to increase the speed of control.

The variable segment characteristics can be compensated if the preceding control unit is used in parallel to the actual pressure difference opening the valve for adjusting the pressure difference.

The preceding control takes place in the control software. The pressure circuit is controlled in advance in terms of disturbance variable compensation. This preliminary control is used for all types of discs and operates with only one pressure chamber for a pair of discs. One valve is also possible for each disc, which is a variant of FIG.

4 shows the connection between the preceding control valve and the regulating force differential. Negative control differential is underdrive direction, positive overdrive direction. The control differential is supplied by the gear ratio regulator. The preceding control valve can be specified in the characteristic line and the preceding control valve can be opened according to this valve. Characteristic line I represents the disc pair 40, and characteristic line II represents the disc pair 42.

In order to use the conical pulley belt transmission for a long time, the conical surface should be well lubricated. 5 and 6 illustrate the countermeasure of this problem. FIG. 5 is a side view of a conical pulley belt transmission with the conical pulley removed, and the belt 42 surrounds two pairs of conical pulleys and extends along a guide or slide rail 64. The half that is not driven is safely placed on the slide rails 54.

6 is a perspective view of a slide rail 54, consisting of two slide plates connected to a rod 55, which form a guide channel 56 through which the belt passes. The slide rail 54 has the other half of the belt and ribs 58 on the side, and the thickness increases from the end of the slide rail toward the center. At least centrally, the ribs 58 are parallel to the grooves 60. The maximum thickness is at the center of the ribs. In the area of the groove 60, as in FIG. 6, the rib has a Y-shaped cross section. The channel 64 includes a spray tube 66 and in the groove 60 there are spray holes 68 and reinforcement projections 62. Oil is injected from the spray hole to cool the pulley. The design shown can be variously modified as long as oil is continuously supplied to the spaces between the pair of conical pulleys. For example, the channel 64 may be closed to directly couple the spray tube and the spray hole. In this case, the hydraulic line is connected to the channel.

The claims of the invention presented with the application are unbiased official proposals to broaden the scope of the patent protection. The application reserves the right to claim additional combinations of the contents shown in the description and / or drawings. The present examples do not limit the invention. Various modifications are possible within the scope of the invention. Combinations of elements and materials by those skilled in the art are possible.

Claims (18)

A method for determining the number of revolutions of a part of a plurality of parts included in a system that is subject to rotational force vibration, The rotational speed of the parts arranged on the vibrating node is measured and the rotational speed of the part is calculated from the measured rotational speed and the speed ratio between the parts. 2. A method according to claim 1, wherein the rotational speeds of the two parts arranged on the other side of the vibrating node are measured and the average value of the rotational speeds of the parts is used to calculate the number of revolutions of the part. The method of claim 1, wherein in order to determine the input rotational speed of the CVT included in the power system of the vehicle, at least one rotational speed driven by the CVT is measured and the input rotational speed of the CVT is measured. The input rotational speed is calculated as the speed ratio of the CVT and the possible additional speed ratio between the output of the CVT and the wheels. 4. The power transmission system of claim 3, wherein at least one wheel speed, input speed and output speed of the CVT are measured and the transmission speed is calculated in the calculations and the additional speed ratio between the output of the CVT and the wheel controls the power system. Or adjusting. 4. A method according to claim 3, wherein the measured and calculated gear input revolutions are used for a given weight for controlling and / or adjusting the power system. 6. A method according to claim 5, wherein the weight depends on the transmission ratio of the CVT. In the method of determining the slip of the CVT, -The rate of change of the transmission ratio is determined, The rate of change determined is compared with the rate of change calculated from the operating parameters of the CVT, The slip is checked if the difference between the predetermined rate of change and the calculated rate of change exceeds a certain level. 8. The method according to claim 7, wherein the calculated maximum value of the rate of change is proportional to 1 / speed ratio ⁿ , n is a value of 1.5 to 2, and the slip is checked if the rate of change exceeds the predetermined maximum value. In the method of sliding the CVT, At least one audible parameter value of the CVT that changes during the slide is stored, Audible parameters are measured, A method for identifying a slip or impending slip when the measured parameter approaches a stored value. In the method of sliding the CVT, -The instantaneous change in the output speed of the transmission is determined, -If the instantaneous change of the output rotation exceeds the predetermined limit value, it is considered to be at least slippery. In the method of sliding the CVT, A momentary change in force acting on at least one of the wheel brakes of a vehicle equipped with a CVT, A method in which the instantaneous change in force exceeds a predetermined value and is considered at least the impending slip. 12. A method according to any one of claims 7 to 11, wherein the corrective variable of the CVT is adjusted to correspond to the slip when the slip or slip is imminent. In a method of controlling a CVT with a belt surrounding a pair of conical pulleys, each conical pulley pair consisting of a single pressure chamber subjected to hydraulic pressure by adjusting the contact pressure between the conical pulley pair and the belt to adjust the transmission ratio of the CVT, in this method A method of opening a cross section of a control valve is characterized in that it comprises a hydraulic line of the pressure chamber and functions as a pressure difference in the pressure chamber for a predetermined speed ratio change rate required to be controlled in advance. In the conical pulley belt transmission, The distance between two conical pulley pairs with two cones is adjustable and the belt wraps around the conical pulley, at least one rib extends parallel to the belt at the end of the slide rail guide on one side of the belt and centers on the slide rail Increase in thickness, and In the center of the ribs there is a tube and extends perpendicular to the belt, injecting liquid into the space between the conical pulleys, A conical pulley belt transmission characterized in that the ribs facing each other at the surface have a groove in the center, and liquid is injected into the hole formed in the pipe passing through the groove to directly reach the space between the conical pulleys. 12. A conical pulley belt transmission as claimed in claim 11 wherein liquid is injected from at least one additional hole in the tube directly reaching the other side. 14. Method according to one of the preceding claims, characterized in that an evaluation operation for damage to the conical pulley belt transmission is started when a slip is detected. 17. The method of claim 16, wherein the measurement for deepening operation is initialized with an evaluation function. 18. The method according to claim 16 or 17, wherein the assessment of the damage is carried out in the form of a measure of the output of the slip.